<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

</body>
<script>
    window.onload = function () {
        let str = 'nihao---'
        let fn = (str)=> {
            alert(str)
        }
        fn(str)
    }
</script>
</html>
